1. Field of the Invention
The subject invention relates to alignment devices and, more particularly, to devices for aligning an antenna with a satellite.
2. Description of the Invention Background
The advent of the television can be traced as far back to the end of the nineteenth century and beginning of the twentieth century. However, it wasn't until 1923 and 1924, when Vladimir Kosma Zworkykin invented the iconoscope, a device that permitted pictures to be electronically broken down into hundreds of thousands of components for transmission, and the kinescope, a television signal receiver, did the concept of television become a reality. Zworkykin continued to improve those early inventions and television was reportedly first showcased to the world at the 1939 World's Fair in New York, where regular broadcasting began.
Over the years, many improvements to televisions and devices and methods for transmitting and receiving television signals have been made. In the early days of television, signals were transmitted and received through the use of antennas. Signal strength and quality, however, were often dependent upon the geography of the land between the transmitting antenna and the receiving antenna. Although such transmission methods are still in use today, the use of satellites to transmit television signals is becoming more prevalent. Because satellite transmitted signals are not hampered by hills, trees, mountains, etc., such signals typically offer the viewer more viewing options and improved picture quality. Thus, many companies have found offering satellite television services to be very profitable and, therefore, it is anticipated that more and more satellites will be placed in orbit in the years to come. As additional satellites are added, more precise antenna/satellite alignment methods and apparatuses will be required.
Modern digital satellite communication systems typically employ a ground-based transmitter that beams an uplink signal to a satellite positioned in geosynchronous orbit. The satellite relays the signal back to ground-based receivers. Such systems permit the household or business subscribing to the system to receive audio, data and video signals directly from the satellite by means of a relatively small directional receiver antenna. Such antennas are commonly affixed to the roof or wall of the subscriber's residence or are mounted to a tree or mast located in the subscriber's yard. A typical antenna constructed to receive satellite signals comprises a dish-shaped receiver that has a support arm protruding outward from the front surface of the dish. The support arm supports a low noise block amplifier with an integrated feed “LNBF”. The dish collects and focuses the satellite signal onto the LNBF, which is connected, via cable, to the subscriber's television.
To obtain an optimum signal, the antenna must be installed such that the centerline axis of the dish, also known as the “bore site” or “pointing axis”, is accurately aligned with the satellite. To align an antenna with a particular satellite, the installer must be provided with accurate positioning information for that particular satellite. For example, the installer must know the proper azimuth and elevation settings for the antenna. The azimuth setting is the compass direction that the antenna should be pointed relative to magnetic north. The elevation setting is the angle between the Earth and the satellite above the horizon. Many companies provide installers with alignment information that is specific to the geographical area in which the antenna is to be installed. Also, as the satellite orbits the earth, it may be so oriented such that it sends a signal that is somewhat skewed. To obtain an optimum signal, the antenna must also be adjustable to compensate for a skewed satellite orientation.
The ability to quickly and accurately align the centerline axis of antenna with a satellite is somewhat dependent upon the type of mounting arrangement employed to support the antenna. Prior antenna mounting arrangements typically comprise a mounting bracket that is directly affixed to the rear surface of the dish. The mounting bracket is then attached to a vertically oriented mast that is buried in the earth, mounted to a tree, or mounted to a portion of the subscriber's residence or place of business. The mast is installed such that it is plumb (i.e., relatively perpendicular to the horizon). Thereafter, the installer must orient the antenna to the proper azimuth and elevation. These adjustments are typically made at the mounting bracket. Prior mounting brackets commonly employ a collection of bolts that must first be loosened to permit the antenna to be adjusted in one of the desired directions. After the installer initially positions the antenna in the desired position, the locking bolts for that portion of the bracket are tightened and other bolts are loosened to permit the second adjustment to be made. It will be appreciated that the process of tightening the locking bolts can actually cause the antenna to move out of its optimum position which can deteriorate the quality of the signal or, in extreme situations, require the installer to re-loosen the bolts and begin the alignment process over again. Furthermore, such mounting apparatuses cannot accommodate relatively fine adjustments to the antenna. In addition, because such crude bracket arrangements are attached directly to the rear of the dish, they can detract from the dish's aesthetic appearance.
One method that has been employed in the past for indicating when the antenna has been positioned at a proper orientation is the use of an inclinometer and a compass that is manually supported by the installer under the antenna's support arm. When using this approach however, the installer often has difficulty rotating the dish to the proper azimuth and elevating the dish to the proper elevation so that the antenna will be properly aligned and then retaining the antenna in that position while the appropriate bolts and screws have been tightened. The device disclosed in U.S. Pat. No. 5,977,922 purports to solve that problem by affixing a device to the support arm that includes a compass and an inclinometer.
Another method that has been used in the past to align the antenna with a satellite involves the use of a “set top” box that is placed on or adjacent to the television to which the antenna is attached. A cable is connected between the set top box and the antenna. The installer initially points the antenna in the general direction of the satellite, and then fine-tunes the alignment by using a signal strength meter displayed on the television screen by the set top box. The antenna is adjusted until the onscreen meter indicates that signal strength and quality have been maximized. In addition to the onscreen display meter, many set top boxes emit a repeating tone. As the quality of the signal improves, the frequency of the tones increases. Because the antenna is located outside of the building in which the television is located, such installation method typically requires two individuals to properly align the antenna. One installer positions the antenna while the other installer monitors the onscreen meter and the emitted tones. One individual can also employ this method, but that person typically must make multiple trips between the antenna and the television until the antenna is properly positioned. Thus, such alignment methods are costly and time consuming.
In an effort to improve upon this shortcoming, some satellite antennas have been provided with a light emitting diode (“LED”) that operates from feedback signals fed to the antenna by the set top box through the link cable. The LED flashes to inform the installer that the antenna has been properly positioned. It has been noted, however, that the user is often unable to discern small changes in the flash rate of the LED as antenna is positioned. Thus, such approach may result in antenna being positioned in an orientation that results in less than optimum signal quality. U.S. Pat. No. 5,903,237 discloses a microprocessor-operated antenna pointing aid that purports to solve the problems associated with using an LED indicator to properly orient the antenna.
Such prior antenna mounting devices and methods do not offer a relatively high amount of alignment precision. Furthermore, they typically require two or more installers to complete the installation and alignment procedures. As additional satellites are sent into space, the precision at which an antenna is aligned with a particular satellite becomes more important to ensure that the antenna is receiving the proper satellite signal and that the quality of that signal has been optimized. With closely spaced satellites, installers may, if not careful, find they have aligned and peaked the antenna to the wrong satellite if they rely solely on signal strength meters. Only after evaluation with a set top box or other identifier might they determine that the signal is incorrect and further alignment corrections are required.
Thus, there is a need for a portable antenna alignment tool that offers the precision of a set top box, yet can be used by a single installer at the antenna installation.
Yet another need exists for a portable tool that has the above-mentioned characteristics that is rugged and weatherproof.
Another need exists for a tool having the above-mentioned attributes that is equipped with a strap and/or belt hook for portability purposes.
Still another need exists for a tool with the above-mentioned attributes that can generate an audio signal indicative of the antenna's alignment with a satellite.
Another need exists for a tool with the above-mentioned attributes that is equipped with an audio port to enable the installer to employ a headset for monitoring the audio signal generated by the tool that is indicative of the antenna's alignment with a satellite.
Yet another need exists for an antenna alignment tool that can be used to precisely align an antenna with a particular satellite that may be spaced, for example, at two degrees with respect to other adjacent satellites.
Another need exists for a portable antenna alignment device that is equipped with a meter for providing a visual indication of the alignment accuracy of an antenna and a satellite.
Still another need exists for an antenna installation method that can be quickly and efficiently employed by a single installer to precisely orient an antenna with a particular satellite without having to make several trips between the antenna and a television set to which its is coupled.